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Cardiomyopathy remains one of the leading causes of sudden death in
children and young athletes although in many subjects the specific defect remains unknown. In most of these
cases the disease has a genetic cause that can be classified into four categories: a) inborn errors of metabolism,
mostly associated with systemic symptoms and transmitted as recessive pattern; b) malformation syndromes with
minor or major anomalies that can often be attributed to a particular etiology; c) neuromuscular disease,
affecting the lower motor unit at the level of the peripheral nerve or skeletal muscle, transmitted with all
mendelian patterns, autosomal dominant, recessive, X-linked or via mitochondrial DNA; d) familial isolated
cardiomyopathy, transmitted mainly as autosomal dominant trait and that cover most of the adult forms.
Although all the above mentioned forms are often referred as cardiomyopathy, this definition should be used only
for the “primary” forms.
The term “cardiomyopathy” was introduced by Brigden in 19571 to distinguish between myocardial disease of
unknown cause and the more commonly recognised myocardial abnormalities arising from systemic hypertension,
coronary artery disease, and valvular disease. Later, a WHO/ICSF Task Force in 19802 defined cardiomyopathies
as “heart muscle disease of unknown cause” as distinct from “specific heart muscle disease”, which are
associated with specific or systemic disorders. Three forms of primary cardiac diseases were distinguished:
hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy (DCM), and restrictive cardiomyopathy (RCM).
Fifteen years later, the new WHO/ICSF Task Force (1995)3 added a fourth form, the arrhythmogenic right
ventricular cardiomyopathy and introduced a subclassification for each of this forms that raised quite a wide
debate among cardiologists.
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